In order to realize high efficiency flotation of hard-to-float coking coal, a composite collector (B2) was prepared by mixing kerosene (B1) with isomeric alcohol ethoxylates 1305 (TO-5). Comparative study on the flotation effect, flotation kinetic properties and frothing performance under multi-stage flotation of B1 and B2 on hard-to-float coking coal. Comparison test results of B1 and B2 flotation effect show that: B1 dosage of 3000 g/t in the low level of foaming agent flotation index decreased significantly, while B2 of only 1000 g/t dosage can be obtained with similar ash content but higher yield of clean coal products compared to B1. The flotation kinetic tests and fitting results showed that the R2 of the fitting using the classical first-order kinetic model under different reagents regimes were all above 0.999. The k value of B1 was 1.3439 at 3000 g/t, and the k value was 1.5809 and 1.7203 at 1000 g/t and 3000 g/t of B2,respectively, indicating that the flotation rate of B2 was faster. The timed-release test curves predict that B2 can achieve higher clean coal yields when B1 and B2 have the same clean ash. Surface tension tests revealed that B1 was unable to reduce the surface tension at the gas/liquid interface, while B2 significantly reduced the surface tension at the gas/liquid interface due to the addition of surfactant TO-5. A visual observation study of the bubbles distributed in the range of 10-1000 μm using a high-speed camera system revealed that the number of bubbles in B1-generated bubbles was little and the size of bubbles was large; the number of bubbles generated with B2 increased significantly. The combination of B2 and 2-octanol improves the probability of collision between bubbles and coal particles by generating smaller and denser flotation bubbles. Laser particle size testing of the bubbles revealed that the volume fraction of microbubbles in the size range of 0.1-1 μm increased significantly for B2 compared with that of B1. B2 enhanced the flotation effect of hard-to-float coking coal by changing the bubble characteristics during flotation. The study provides a reference for the research and development of highly efficient trapping agents for hard-to-float coking coal.